Chuck



De.21,194s. Y E. BUGATTI 2,457,030..

cHucKI Filed sept. 11. 1945"Y Patented Dec. 21, 1948 UNITED .STATESPATENT `OFFICE.

Application-September 11, 1945, Serial No. 615,634. In France May 16,1944 Section 1, Public Law 690, August 8, 1946 Patent expires May 16,1964 `8 Claims.

The chucks utilized for holding 'the work to be .turned on a lathe musthave their jaws rigorously centered .on the axis lof the headstock, andkeep this property even after a prolonged use.

The influence ci the vvarious "plays resulting either from constructionor from wear `and capable of alterating centering is too knownfor itbeing necessary to set forth the effects thereof.

.In particular, the rim` which is fa member com mon to `all Vtypes ofchucks `(said rim having, on cneace, Aa bevel zgea-r vmeshing with theconical control pinions and, on the uother face., a spiral groove -orscroll the rotation yof which causes aXial shifting of the jaws) turnswithin a hollow cylinder constituting the casing oit the chuck,'withclearance either on its outer'periphery or on its inner periphery.

Now, it is known .that concentricity ci vjaws is strictly dependent -onthe holding of said rim, the offsetting ci which causes a correspondingshifting of the jaws. Itis then indispensable to provide for the rim acentering with a minimum play either inside the casing or 'on thecentral male lpart, or hub, of said casing.

In usual practice, .one -is limited in this way by the fact that the rimmust turn very freely in its housing or on the hub and by otheroonsiderations inherent in the method oi construc tion of chucks (riskyof jamming of jaws, etc).

This invention has for an object to provide means whereby toothed .rimof chucks `are centered without play while ythey may rotate freely. -Afurther object is to provide means which compensate automatically forplay resulting from wear, and contribute to keep concentricity of chuckslafter a .long use.

According to my invention, a chuck rim is mounted with an amount of play`in its outer casing, and `between the inner bore of the rim Aand thehub which carries said rim, an automatic or manually adjustable devicefior taking up play is provided. Said device, constituted essentially byan expansible circular bearing automatically centers the rim on the .huband consequently on the axis Aof the chuck. .f

4in a nrst advantageous embodiment .of-this invention, the expansiblebearing is constituted by a pair of concentrical conical rings' atAleast one of which, is .split yand ladapted to expand when the other isaxially moved by a spring orotfher similar member.

In another embodiment, the hub of the chuck or else the bore of the vrimis conical. In this case, there is provided one conical ringmade ofindependent segments.

Finally, Athe .same result may ybe obtained `by using la row vof ballsor possibly conical rollers resting on Va conical ballwace on the ria-n,and on a cylindrical balia-ace cont-ered on the hub; the latter`balL-race may .be -axially shifted either through .a thread on the hub,or by a spring. Conversely, 'a conical lball-.race integral with the hubmay .be combined with a cylindrical 'ball-race provided in the rim. Thelatter ball-.race is stationary when that on the hub is movable, ormovable when the latter is stationary.

The following description with reference to the appended drawings givensolely by way of eX ample will show `how this invention may be carriedout.

Fig. l is a partial Vcross section of a chuck according to thisinvention.

Fig. 2'show-s a detail according to another em- .bod-intent of 'thisinvention.

1li-g3 shows ya modication of the device shown on Fig. 2.

Fig.. 4, correlated with Fig. 3,'sl1cws a detail common to Figs. Zand 3.

Fig. 5 shows, as a modification, another embodiment of this invention.

Fig. 6 shows a device derived from that shown on Fig. 5.

The -body l of the chuck represented on Fig. l. by Way of illustrationconstitutes the casing for said chuck .and confines .all the usualcomponent members, the rim 2 alone being represented. Control pinionsmeshing with the bevel gearing -face 3 of -r-im 2, 4and the jaws slidingin suitable grooves provided v.in the bottom 4.- lof casing l are notrepresented. It will be assumed that the cross .section .shown on Fig. 1vhas been made by a plane containing `neither the `pinion axis nor thatof the jaws.

.A Acover .5, the threaded portion libia ci which is screwed on theshaft oi the headstock is centered in. the bore 6 oi casing i, and bothmembers are `united by means of screws not shown on the figure. Anamount of play is provided between the outer surface l of rim i? and theinner surface'f oi easing i; said surfaces must not, in any case,cc'me'nto contact with one another.

Rim :v2 bears on the face lll of bottom 4 through its .tace 9 which hasa spiral or scroll gearing corresponding to that ofthe jaws, so as toleave a normal clearance between the teeth of face 3 and those oi theconical control pinions.

A ring H, which is outwardly conical, is borne on hub l2 of casing l.Said. ring il comprises, for the best, aseries of seg-ments in order to.preclude clearance between its bore andthe outer surface of hub I2;said clearance would be unavoidable if ring II was made oi one part.

An inwardly conical ring I3 is fitted on ring II and tends to beexpanded by the thrust of a spring Ill.

Spring ill is backed by the bottom 4 of casing I, ring I3 reactingagainst the spring thrust by abutting :against the hub I5 of cover 5.Splits |30 which partly out the ring I3, give the latter sufficientresiliency to cause the male and female cones, when eng-aged, slightlyto squeeze ring I3 in the bore IE5 of rim 2. Rim 2 thus turns withoutplay on ring I3, the close fit being determined by the strength oispring ld and th-e apex angle of conical rings II and I3.

Rim il wears where there is a friction, that is to say in bore I6 and onthe outside of ring I3, rand wear is automatically compensated for by acorresponding axial shifting of ring I I.

In the example shown on Fig. 2, a single ring I'I, which is inwardlyconical, is used; said ring, resting on a conical surface I8 on the hubI2 of casing I, tends to expand and to lill the bore I6 of rim 2. rIhisr-esult is obtained owing to the fact 'that ring I'I is comprised of aseries of segments, and is continuously urged by la spring I9 backed byhub I5 of -cover 5. Said spring I9 may be shaped as a thin steel ringhaving undulatons (Fig. 4). The various segments such as IIa and Ilbwhich constitute ring I I have a straight or an oblique cut; in thelatter case, the sli-ding conditions in bore I6 of rim 2 when the latterturns, are improved.

In order to prevent ring I'I from being driven round by rim 2 pins 2lset in hub I2 are inserted in each gap such as 28 which separate thesegments of ring I'I.

In the modification shown on Fig. 3, ring 22 is conical outwardly andtends to fill the inner cone 23 of rim 2. Like ring I'i, ring 22 isconstituted by a series of segments, this lallowing of removingclearance both along hub I2 and rim 2. The device acts exactly like thatof Fig. 2.

In the embo-diment shown on Fig, 5, the ring 2li made of special steelis forced into a housing 25 provided in the centre of rim 2. Thediameter of the bore 26 of rim 2 is appreciably greater than thediameter of part 21 of hub I2 which faces said bore.

Rim 2 is centered through a row of balls 28 rolling both in the innercone 290i ring 24 and on the inner ring Si), itself screwed on hub I2.When mounting the chuck, it is only necessary to screw ring 3c by m-eansof castellations 3| until there is no more play between balls 28 and thetwo ballraces 29 and 3U; however care should be taken in order that rim2 may still turn freely.

The play resulting from wear is periodically removed; to this end, thechuck cover 5 is disassembled and ring 33 is screwed by the required`amount.

The same result is automatically obtained with the device shown on Fig.6, in which a spring 32', similar to above'mentioned springs I 4 or I9,allows of compensating for Wear by constantly pushing race 33 in whichroll balls 26.

The embodiment shown on Figs. 5 and 6 is based on the use ci balls. Thelatter may advantageously be replaced by conical rollers rolling onrings similar to rings 2li and 30 or 33. In this order of idea, it isadvisable to use commercial bearings of the Timken kind, the outer ringof which would be forced into rim 2 while the inner ring would slide onhub I2, being urged by a threaded washer or a spring. y

r ment member.

It will be obvious that minor alterations may be brought about in theforegoing embodiments, especially by using equivalent technical means,without departing from the spirit of the appended claims.

What I claim is:

1. In a chuck of the type described, the combination of a chuck bodyhaving a hub; a jaw control ring loosely mounted on said hub forrotation thereon; and radially 'expansible means interposed between saidhub and the inner periphery of said ring for bearing said ring from saidhub and taking up clearance therebetween.

2. In a chuck of the type described, the combination vof a chuck bodyhaving a hub; a jaw control ring losely mounted on said hub for rotationthereon; a radially expansible means, adapted to be operated by axialthrust thereon, interposed between said hub and the inner periphery ofsaid ring, for bearing said ring from said hub and taking up clearancetherebetween; and resilient means backed from said chuck body, foraxially pushing the expansible means. f

3. In a chuck of the type described, thecombination of a chuck bodyhaving a hub; a ring on said hub, having a close fit therewith, theouter periphery thereof being conical; a split ring with a cylindricalouter periphery and an inner conical periphery on the first ring; a jawcontrol ring'revolubly borne with a close fit on said split ring; andresilient means for urging the rst two rings towards one another inaxial direction.

4. In. a chuck of the type described, the combination of a chuck bodyhaving a hub; a ring on said hub, having a close it therewith, the outerperiphery thereof being conical; a split ring with a cylindrical outerperiphery and an inner conical periphery on the first ring; a jawcontrol ring revolubly borne wth a close t on said split ring; means onsaid hub providing abutments for each one of the rst two rings, oneither side of said rings, one of said abutments being resilient and oneof said abutments being adjustable.

5. In a chuck of the type described, the combination of a chuck bodyhaving a hub Witha stationary abutment thereon; a ring on said hub, onone side of said abutment, having a close nt with said hub; a split ringwith a cylindrical outer periphery and an inner conical periphery. onthe first ring; a jaw control ring revolubly borne on the split ring;resilient means operatively interposed between one of the first tworings and the stationary abutment, for urging said ring in one axialdirection; and means adjustably secured on said hub, providing anadjustable abutment for the other of said first two rings.

6. In a chuck of the type described, the combination of a pair ofmembers, to wit va chuck body having a hub, and a jaw control ringloosely tted on said hub for rotation thereon, one of said membershaving a conical bearing surface facing the other member; meansindiscontinuous ring formation, between said members, having a conicalsurface for contact with'said conical bearing surface of one of saidmembers, providing a bearing for the jaw control ring on the chuck hub;an abutment .member secured Yon said hub in an axially adjustableposition; and a sinuous resilient steel strip in ring formation,interposed between said means and said abut- 7. In a chuck of the typedescribed, the combination of a pair of members, to wit a chuck bodyhaving a hub, and a jaw control ring loosely fitted on said hub forrotation thereon, one of said members having a conical bearing surfacefacing the other member; means in discontinuous ring formation, betweensaid members, having a conical surface for contact with said conicalbearing surface of one of said members, providing a bearing for the jawcontrol ring on the chuck hub; at least one stop member in outwardlyprotruding position on said hub, projection into a gap of saiddiscontinuous ring means, for holding the latter against rotation; andmeans adjustably secured on said hub, in operative contact Wtih thefirst-named means for urging the same in wedging direction.

8. In a chuck of the type described, the combination of a chuck bodyhaving a hub; a jaw control ring loosely fitted on said hub for rota;-tion thereon; and means providing a bearing for said ring on said hub,including a set 0f rollers between. non parallel, co-axial roller racesone of which is adjustable in axial position.

ETTORE BUGATTI.

REFERENCES CITED The following references are of record in the ie ofthis patent:

UNITED STATES PATENTS

